Float operated cistern tank fill valves are known. However, conventional fill valves suffer from several disadvantages. Cistern fill valves are typically utilized to control the filling of water supply reservoirs or receptacles which receive water from a municipal supply. In many instances, the cistern may only be filled during a specific time period requiring that the reservoir be filled as quickly as possible. One drawback of the prior known fill valves is the tendency to throttle-down the fluid flow as the float approaches the fill line. This can substantially increase the time needed to completely fill the cistern particularly in tanks with a large surface area.